A : Thin films such as soap bubble or a thin layer of oil on water show beautiful colours when illuminated by sunlight.
R : The colours are obtained by dispersion of light only.

Options

A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true and R is not the correct explanation of A
C. A is true and R is false
D. Both A and R are false

Answer

To solve the question, we need to analyze both the assertion (A) and the reason (R) statements provided.

### Step 1: Analyze the Assertion (A)
The assertion states: "Thin films such as soap bubble or a thin layer of oil on water show beautiful colors when illuminated by sunlight."

- **Explanation**: This statement is true. Thin films like soap bubbles and oil on water do indeed display a range of colors when illuminated by sunlight. This phenomenon occurs due to the interaction of light with the thin film, which leads to interference effects.

### Step 2: Analyze the Reason (R)
The reason states: "The colors are obtained by dispersion of light only."

- **Explanation**: This statement is false. While dispersion can cause separation of colors (as seen in a prism), the colors observed in thin films are primarily due to interference of light waves reflecting off the different surfaces of the film.

### Step 3: Conclusion
Since the assertion is true and the reason is false, we conclude that:

- **Assertion (A)**: True
- **Reason (R)**: False

### Final Answer
The correct option is that the assertion is true, but the reason is false.

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